KUALA LUMPUR, March 17 The co-pilot of a missing
Malaysian jetliner spoke the last words heard from the cockpit,
the airline's chief executive said on Monday, as investigators
consider suicide by the captain or first officer as one possible
explanation for the disappearance.

No trace of Malaysia Airlines Flight MH370 has
been found since it vanished on March 8 with 239 people aboard.
Investigators are increasingly convinced it was diverted perhaps
thousands of miles off course by someone with deep knowledge of
the Boeing 777-200ER and commercial navigation.

A search unprecedented in its scale is now under way for the
plane, covering an area stretching from the shores of the
Caspian Sea in the north to deep in the southern Indian Ocean.

Airline chief executive Ahmad Jauhari Yahya also told a news
conference that it was unclear exactly when one of the plane's
automatic tracking systems had been disabled, appearing to
contradict the weekend comments of government ministers.

Suspicions of hijacking or sabotage had hardened further
when officials said on Sunday that the last radio message from
the plane - an informal "all right, good night" - was spoken
after the tracking system, known as "ACARS", was shut down.

"Initial investigations indicate it was the co-pilot who
basically spoke the last time it was recorded on tape," Ahmad
Jauhari said on Monday, when asked who it was believed had
spoken those words.

That was a sign-off to air traffic controllers at 1.19 a.m.,
as the Beijing-bound plane left Malaysian airspace.

The last transmission from the ACARS system - a maintenance
computer that relays data on the plane's status - had been
received at 1.07 a.m., as the plane crossed Malaysia's northeast
coast and headed out over the Gulf of Thailand.

"We don't know when the ACARS was switched off after that,"
Ahmad Jauhari said. "It was supposed to transmit 30 minutes from
there, but that transmission did not come through."

FOCUS ON CREW

The plane vanished from civilian air traffic control screens
off Malaysia's east coast less than an hour after taking off
from Kuala Lumpur. Malaysian authorities believe that someone on
board shut off its communications systems as the plane flew
across the Gulf of Thailand.

Malaysian police are trawling through the backgrounds of the
pilots, flight and ground staff for any clues to a possible
motive in what they say is now being treated as a criminal
investigation.

Asked if pilot or co-pilot suicide was a line of inquiry,
Malaysian Acting Transport Minister Hishammuddin Hussein said:
"We are looking at it." But it was only one of the possibilities
under investigation, he added.

Intensive efforts by various governments to investigate the
backgrounds of everyone on the airplane had not, as of Monday,
turned up any information linking anyone to militant groups or
anyone with a known political or criminal motive to crash or
hijack the aircraft, U.S. and European security sources said.

One source familiar with U.S. inquiries into the
disappearance said the pilots were being studied because of the
technical knowledge needed to disable the ACARS system.

Many experts and officials say while the jet's transponder
can be switched off by flicking a switch in the cockpit, turning
off ACARS may have required someone to open a trap door outside
the cockpit, climb down into the plane's belly and pull a fuse
or circuit breaker.

Whoever did so, had to have sophisticated knowledge of the
systems on a 777, according to pilots and two current and former
U.S. officials close to the investigation.

Malaysian police special branch officers searched the homes
of the captain, 53-year-old Zaharie Ahmad Shah, and first
officer, 27-year-old Fariq Abdul Hamid, in middle-class suburbs
of Kuala Lumpur close to the international airport on Saturday.

Among the items taken for examination was a flight simulator
Zaharie had built in his home.

A senior police official familiar with the investigation
said the flight simulator programmes were closely examined,
adding they appeared to be normal ones that allow users to
practise flying and landing in different conditions.

A second senior police official with knowledge of the
investigation said they had found no evidence of a link between
the pilot and any militant group.

Some U.S. officials have expressed frustration at Malaysia's
handling of the investigation. As of Monday morning the
Malaysian government still had not invited the FBI to send a
team to Kuala Lumpur, two U.S. security officials said.

The FBI, which has extensive experience in investigating
airplane crashes, and other U.S. law enforcement agencies have
indicated they are eager to send teams to Kuala Lumpur, but will
not do so unless formally invited.

VAST SEARCH CORRIDORS

Police and a multi-national investigation team may never
know for sure what happened in the cockpit unless they find the
plane, and that in itself is a daunting challenge.

Satellite data suggests it could be anywhere in either of
two vast corridors that arc through much of Asia: one stretching
north from Laos to the Caspian, the other south from west of the
Indonesian island of Sumatra into the southern Indian Ocean west
of Australia.

Aviation officials in Pakistan, India, and Central Asian
countries Kazakhstan and Kyrgyzstan - as well as Taliban
militants in Pakistan and Afghanistan - said they knew nothing
about the whereabouts of the plane.

China, which has been vocal in its impatience with Malaysian
efforts to find the plane, called on its smaller neighbour to
immediately expand and clarify the scope of the search. About
two-thirds of the passengers aboard MH370 were Chinese.

Australian Prime Minister Tony Abbott said he had spoken to
Malaysian counterpart Najib Razak by telephone, and had offered
more surveillance resources in addition to the two P-3C Orion
aircraft his country has already committed.

Malaysian Transport Minister Hishammuddin said diplomatic
notes had been sent to all countries along the northern and
southern search corridors, requesting radar and satellite
information as well as land, sea and air search operations.

The Malaysian navy and air force were also searching the
southern corridor, he said, and U.S. P-8A Poseidon surveillance
aircraft were being sent to Perth, in Western Australia, to help
scour the ocean.

NORTH OR SOUTH?

Electronic signals between the plane and satellites
continued to be exchanged for nearly six hours after MH370 flew
out of range of Malaysian military radar off the northwest
coast, following a commercial aviation route across the Andaman
Sea towards India.

The plane had enough fuel to fly for about 30 minutes after
that last satellite communication, Ahmad Jauhari said.

Twenty-six countries are involved in the search, stretching
across much of Asia.

A source familiar with official U.S. assessments of
satellite data being used to try to find the plane said it was
believed most likely it turned south sometime after the last
sighting by Malaysian military radar, and may have run out of
fuel over the Indian Ocean.

The Malaysian government-controlled New Straits Times on
Monday quoted sources close to the investigation as saying data
collected was pointing instead towards the northern corridor.

SAO PAULO, Dec 9 The Brazilian government will
extend subsidized credit to companies interested in bidding for
airport operating licenses so long as they agree to strict
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monitor project execution.

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